The proposed work aims to elucidate the primary structure of the human pituitary gonadotropic hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH). This has already been accomplished and has been published by the principal investigators. The proposed work aims also to elucidate the nature of the carbohydrate moieties of FSH and LH and to illumine, also, the reactive groups of these two protein hormones which regulate reproduction. The information gained in these studies will be utilized to design means of counteracting the biologic activities of these hormones, with a view to achieving contraception in this way.